Guide and grandfather, Lin Zhengtang: He is no ordinary barefoot doctor. In his youth, he may have been the renowned “Ghost-Hand Miracle Doctor” of the “Hidden World.” He refused to go along with corruption and was ambushed, forcing him to hide his identity. His diary is the most precious clue he leaves the protagonist.
· Nemesis, Gu Qinghong: An heir to a family of doctors, young, promising, and graceful. He sees the protagonist as a “country bumpkin” who breaks the rules, making him the protagonist's best benchmark and greatest source of pressure in the early days in the “Surface World.” His presence drives the protagonist to keep reaching higher.
· Confidante, Su Muxue: The heiress of a pharmaceutical group, aloof on the outside but kindhearted within. She initially approaches the protagonist for business reasons, but is won over by his character and medical skills. She becomes an important bridge connecting him to the resources of the city's upper class.
· Comrade-in-arms, Tie Niu: The protagonist's childhood friend from the slums, strong-built and honest. He is the protagonist's staunchest support, handling all the “muscle” and “comic relief.”
